Deicing fluids are used to remove frozen, or partially frozen, deposits of ice and snow from surfaces which are required to be free from such contamination. Anti-icing fluids prevent, for a limited time, the refreezing of water on treated surfaces. Both types of fluid are well known in the art. It is necessary for ongoing airport operations, during periods of freezing precipitation, to apply deicing/anti-icing fluids. The longer the time interval from when the anti-icing fluid is applied to a freshly decontaminated surface, until the onset of re-freezing on that surface, the greater the advantage to the user. The standard method of assessing this time delay is the Water Spray Endurance Test (WSET), which is fully described in an appendix to the SAE/AMS 1428.
Prior art anti-icing fluids rely heavily upon thickening polymers to achieve performance, and have apparent viscosities in the range 15,000 to 55,000 mPas. when measured at 20.degree. C. This inherent thickness lays down a thick layer. It is this volume thickness of glycol which is the greatest contributor to retarding the onset of re-freezing. The present minimum standard for type II fluids is 30 minutes and a type I is 3 minutes.